Why Are Steel-Shell Lithium Batteries Cheaper Than Polymer Ones?

In terms of structure and material cost, steel-shell batteries use standardized cylindrical enclosures and mature production lines with high automation and low unit manufacturing cost. Polymer batteries use aluminum-laminated film packaging, which requires additional forming, sealing and formation/sorting processes with tighter yield control, hence a higher cost.

Neither option is absolutely better: steel-shell suits cost-sensitive, highly standardized applications, while polymer offers greater freedom of shape, lower weight and higher energy density, ideal for slim and irregular product designs.